The present invention relates generally to high speed winding of filamentary material onto bobbins or spools to form packages of filamentary material. More particularly, it relates to the handling of man-made filament yarn (continuously fed at say 100 mph) during removal of a full package (sidewound, crosswound yarn on a tube) and transfer of the continuously fed filament yarn onto an empty, rotating, flangeless tube, after which a further yarn package is formed.
The manufacture of man-made or synthetic filament yarns is typically achieved by extruding a molten polymer, such as polyester, polyamide, etc., through hole(s) in a spinneret and then cooling the filament(s) thus formed. Thereafter, the filaments may be gathered together to form a multi-filament yarn and, possibly after further treatment, are wound onto a tube so that a yarn package is formed.
Winding of the yarn is performed mechanically by winders which rotate one or more packages to wind-up the yarn while traversing the yarn along the package axis to achieve a uniform thickness of yarn being wound.
A doffing/donning operation (i.e., replacement of the yarn packages with empty tubes on the winder) is often performed manually by an operator who (i) severs the yarn, (ii) stops the rotary drive to the packages; (iii) replaces the packages with empty tubes; (iv) re-establishes the rotary drive; and (v) rethreads the yarn onto the empty tubes. Severing of the filamentary yarn is typically performed with scissors while the inlet of a suction or aspirator gun is held against the yarn at a location above the point of severing. Once the yarn is severed, the tail end is wound onto the yarn package, while the newly formed leading end is sucked into the aspirator and fed to a waste collector. The suction gun is then placed onto a holder while the yarn packages are being replaced by empty tubes. When the empty tubes attain full speed, the operator manipulates the suction gun to attach the yarn to the rotating tubes so that this winding operation may begin.
In order to economize such winding operations, it has heretofore been proposed to mechanize the doffing and donning operations to a certain extent by providing a mechanism which automatically severs, aspirates and rethreads the yarn. Exemplary of proposed mechanisms of that type are the disclosures in U.S. Pat. No. 4,023,741 issued to Schar on May 17, 1977; U.S. Pat. No. 4,052,017 issued to Schar on Oct. 4, 1977; and U.S. Pat. No. 4,108,388 issued to Schar on Aug. 22, 1978.
In the afore-mentioned U.S. Pat. No. 4,023,741, a mechanism is disclosed in which a cutter and aspirator are carried at the end of a reciprocable carrier arm. The carrier arm is extendable toward a pair of traveling yarns in a direction parallel to the yarn package axis such that the cutter sequentially severs the yarns and the aspirator exhausts same to waste while the packages are being removed. A pair of holders are arranged to capture the cut filaments being sent to waste. The carrier arm and the holders are rotatable downwardly together to a location on the opposite side of the winders (i.e., the cutter, aspirator, and holders travel through a vertical plane containing the bobbin axis) to thread the yarn onto the empty tubes. It will be appreciated that by requiring that the cutter and aspirator travel downwardly with the yarn holders, a more complicated mechanism results. Also, by moving the yarn holders through the vertical plane containing the yarn package axis, it is necessary to provide extra guides above the winder to engage and properly orient the yarns during the rethreading procedure. Crossing of the vertical plane also complicates the return of the holders to the upper position because care must be taken to avoid contact of the holders with the rethreaded yarns as the holders pass through the plane of the yarns. Also, the particular path assumed by the yarn holders appears to foreclose any chance that the yarns can be threaded into tailing guides which are commonly employed on yarn winders between the level of the yarn package axis and the level of the yarn traverse guide.
A particular type of cutter mechanism is disclosed in the afore-mentioned U.S. Pat. No. 4,108,388. That cutter mechanism includes a pair of superimposed cutter blades which are relatively movable. The blades include alignable slots which open to the side to admit a yarn directed toward the slot by cam surfaces at the front of the blades. After a yarn enters the slot, it becomes pinched between the relatively moving blades and is severed. It will be appreciated that the side-wise entry direction of the slot demands that a relatively precise alignment occur between the cutter and the yarns to assure that the yarns contact the front cam surface. Also, unless the relative movement between the cutter blades is very rapid, an inadequate cutting action may result because the filaments begin to slacken immediately upon being pinched between the relatively moving blades.
Although it has been heretofore proposed to provide a yarn cutter with scissors-type blades, thereby defining a forwardly open slot, there may not be means for capturing the filaments within the slot. Such a deficiency would not be desirable in cases where the yarn is being traversed and thus may be traveling in a direction away from the cutter at the instances when the blades close, i.e., the filaments may exit the cutter without being cut.
Even in the absence of automatic severing and aspirating, i.e., where a manually operable aspirator "gun" is employed, difficulties can be encountered in "capturing" a yarn for severing, especially when the yarn is located an arm's length or more away from the operator. For example, as is the case in one previously proposed aspirator gun a slot opens in a direction perpendicular to the suction tube. Thus, it is necessary for the operator to guess when the slot and yarns are aligned in order to capture the yarns. This can be a slightly difficult procedure, involving undesirable delays (e.g., see U.S. Pat. No. 3,175,290 issued to Bunting, Jr., et al on Mar. 30, 1965).